Researchers Stimulate Optic Nerve to Aid the Blind

Sunday, August 25, 2019 - 16:40

Scientists from EPFL in Switzerland and Scuola Superiore Sant'Anna have stimulated the optic nerve to to provide visual signals to the blind.

According to the Science Daily report, researchers could develop a new technology for the blind that bypasses the eyeball entirely and sends messages to the brain.

Based on the research, successfully tested in rabbits and released in Nature Biomedical Engineering, researchers stimulated the optic nerve with a new type of intraneural electrode called OpticSELINE.

"We believe that intraneural stimulation can be a valuable solution for several neuroprosthetic devices for sensory and motor function restoration. The translational potentials of this approach are indeed extremely promising," explains Silvestro Micera, EPFL's Bertarelli Foundation Chair in Translational Neuroengineering, and Professor of Bioelectronics at Scuola Superiore Sant'Anna, who continues to innovate in hand prosthetics for amputees using intraneural electrodes.

Intraneural electrodes may indeed be the answer for providing rich visual information to the subjects. They are also stable and less likely to move around once implanted in a subject, according to the scientists. Cuff electrodes are surgically placed around the nerve, whereas intraneural electrodes pierce through the nerve.

Together, Ghezzi, Micera and their teams engineered the OpticSELINE, an electrode array of 12 electrodes. In order to understand how effective these electrodes are at stimulating the various nerve fibers within the optic nerve, the scientists delivered electric current to the optic nerve via OpticSELINE and measured the brain's activity in the visual cortex.

They developed an elaborate algorithm to decode the cortical signals. They showed that each stimulating electrode induces a specific and unique pattern of cortical activation, suggesting that intraneural stimulation of the optic nerve is selective and informative.

As a preliminary study, the visual perception behind these cortical patterns remains unknown. Ghezzi continues, "For now, we know that intraneural stimulation has the potential to provide informative visual patterns. It will take feedback from patients in future clinical trials in order to fine-tune those patterns. From a purely technological perspective, we could do clinical trials tomorrow."

With current electrode technology, a human OpticSELINE could consist of up to 48-60 electrodes. This limited number of electrodes is not sufficient to restore sight entirely. But these limited visual signals could be engineered to provide a visual aid for daily living.

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